1. Field of the Invention
The present invention relates to a soundproof grommet for installing a wiring harness so as to pass through a panel of an automobile.
2. Description of the Related Art
A proposed grommet is provided with a base body including an engaging groove provided on an outer surface thereof, and a waterproof tube portion integrally projected therefrom. The waterproof tube portion receives and closely contacts with a wiring harness inserted thereto so as to be waterproof.
The grommet includes a soundproof envelope which is integrally connected with the waterproof tube portion. The soundproof envelope is turned-over to the base body and is in close contact therewith. Thereby an airtight chamber is formed between the base body and the sound proof envelope so as to be soundproof.
The grommet further includes one or more extra tube portions penetrating the base body.
An art related to the proposed grommet is disclosed in Japanese Patent Application Laid-open No. 2000-104865.
According to the proposed grommet, one or more extra cables may pass through the extra tube portions respectively. In such a case, the soundproof envelope is obstructed by the passing cables so as not to be in close contact with the base body. Therefore sound insulation is reduced.
The present invention is accomplished in view of the above problem and intends to provide a soundproof grommet with excellent sound insulation.
According to a first aspect of the present invention, a soundproof grommet is provided with a base body including an engaging groove provided on an outer surface thereof, a conical wall integrally connected therewith and a main tube portion integrally projected from the conical wall; a soundproof envelope integrally connected with the base body, having a wire supporting portion; and one or more extra tube portions penetrating the conical wall and the soundproof envelope in an integral manner. The main tube portion and the wire supporting portion receive and closely contact with a wiring harness inserted thereto so that the base body and the soundproof envelope form an airtight chamber.
The extra tube portions penetrate both the conical wall of the base body and the soundproof envelope. Thereby the soundproof envelope is not obstructed by the insertion of extra cables. The chamber formed by the base body and the soundproof envelope is always kept airtight so as to assure excellent sound insulation.
According to a second aspect of the present invention, each of the extra tube portions of the grommet described above is further provided with a pair of soundproof walls integrally connected with the conical wall and the soundproof envelope.
In a case where recesses penetrating the base body through the soundproof envelope are provided adjacent to the extra tube portions respectively, the airtightness of the airtight chamber is assured by the soundproof walls instead of the penetrated base body. Thereby excellent sound insulation is assured.